So then what is an optimal muscle training routine for a natural trainee with average to poor genetics?

An optimal muscle training routine to begin with is a standard 3 day a week regimen. Training each body part once a week, splitting the body three ways. For instance , Monday could be chest, shoulders, and triceps. Wednesday could look like Back and Biceps. And Friday would be Legs, or as us hardcore dungeon lifters refer to, "Dreaded Leg Day". From this point the trainee can determine his level of recovery ability, while still building muscle. The routine does not overly tax recovery ability and at the same time the muscles are being worked frequently.